Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| transposon mutagenesis in rhizobia which can nodulate both legumes and the nonlegume parasponia. | the successful use of transposon mutagenesis in a slow-growing rhizobium permitted the isolation of auxotrophic and symbiotically defective mutants. in these mutants, it was shown that different single-copy tn5 insertions had occurred. mutant phenotypes indicated that the control of nitrogenase activity in vitro and in planta is different. | 1982 | 16345924 |
| recognition of leguminous hosts by a promiscuous rhizobium strain. | the lima bean (phaseolus lunatus l.) and the pole bean (phaseolus vulgaris l.) are nodulated by rhizobia of two different cross-inoculation groups. rhizobium sp. 127e15, a cowpea-type rhizobium, can induce effective nodules on the lima bean and partially effective nodules on the pole bean. rhizobium phaseoli 127k14 can induce effective nodules on the pole bean but does not reciprocally nodulate the lima bean. root hairs of the lima bean when inoculated with rhizobium sp. 127e15 showed tip curlin ... | 1982 | 16345975 |
| relative efficacy of different alfalfa cultivar-rhizobium meliloti strain combinations for symbiotic nitrogen fixation. | five rhizobium meliloti isolates known to have different capabilities for expression of nitrogenase activity under symbiotic conditions were used to inoculate four representative medicago sativa cultivars under aseptic conditions. nitrogenase activities and respiratory activity were measured for whole plants and excised nodules. dry weights and nodule numbers were also recorded after 4 weeks of growth in plastic pouches on a nitrogen-free nutrient medium. hydrogen evolution and acetylene reducti ... | 1982 | 16345986 |
| legume-rhizobium interactions: cowpea root exudate elicits faster nodulation response by rhizobium species. | preinfection events in legume-rhizobium symbiosis were analyzed by studying the different nodulation behaviors of two rhizobial strains in cowpeas (vigna sinensis). log-phase cultures of rhizobium sp. strain 1001, an isolate from the plant nodule, initiated host responses leading to infection within 2 h after inoculation, whereas log-phase cultures of rhizobium sp. strain 32h1 took at least 7 h to trigger a discernible response. the delay observed with strain 32h1 could be eliminated by incubati ... | 1982 | 16345989 |
| accumulation of amino acids in rhizobium sp. strain wr1001 in response to sodium chloride salinity. | rhizobium sp. strain wr1001, isolated from the sonoran desert by eskew and ting, was found to be able to grow in defined medium containing nacl up to 500 mm, a concentration approaching that of sea water. therefore, it is a valuable strain for studying the biochemical basis of salt tolerance. intracellular free glutamate was found to increase rapidly in response to osmotic stress by nacl. it accounted for 88% of the amino acid pool when the bacterium was grown in 500 mm nacl. the role of glutama ... | 1982 | 16346049 |
| succinate-induced morphology of rhizobium trifolii 0403 resembles that of bacteroids in clover nodules. | morphological changes which accompany nutrient enrichment of rhizobium trifolii 0403 were studied. assays of cell number and size coupled with scanning electron microscopy and immunofluorescence microscopy showed that succinate induces cells to stop dividing in vitro and to swell either in the cell center or at one cell pole. the extent and frequency of in vitro cell swelling were in direct relation to the concentration of succinate added to the enrichment medium. the in vitro swelling of cells ... | 1982 | 16346058 |
| growth-related substituent changes in exopolysaccharides of fast-growing rhizobia. | pyruvic acid and o-acetyl groups are the major noncarbohydrate substituents in exopolysaccharides (eps) produced by fast-growing species of rhizobium. eps substituent variations were observed among strains of the same species. the amounts of these substituents also varied with culture age; pyruvic acid increased in the eps of all four species, whereas o-acetyl increased in rhizobium trifolii and r. leguminosarum eps, decreased in r. meliloti eps, and remained constant in r. phaseoli eps. the use ... | 1982 | 16346062 |
| root surface association in relation to nodulation of medicago sativa. | nine strains of rhizobium meliloti, ranging in competitive ability on medicago sativa from excellent to poor in autoclaved soils, were paired in 29 combinations and used to inoculate m. sativa in a liquid rooting medium. a positive correlation (r = 0.545) between strain ratios in nodules after 28 days and root surface cell ratios after 7 days was determined. two cell fractions from the root surface, representing loosely and firmly adhering cells, were investigated. infectivity was linked to the ... | 1982 | 16346071 |
| competitive abilities of rhizobium meliloti strains considered to have potential as inoculants. | twenty four strains of rhizobium meliloti considered to have potential for inoculant production were grouped in pairs and tested for their ability to compete for nodulation on medicago sativa, medicago truncatula, and medicago littoralis. at the outset, each pair of strains, which consisted of a wild type and a selected streptomycin-resistant mutant of another strain, was tested in an autoclaved soil. six strain pairs, each consisting of a good and a poor competitor, reacted consistently when te ... | 1982 | 16346072 |
| mass spectrometric quantification of indole-3-acetic acid in rhizobium culture supernatants: relation to root hair curling and nodule initiation. | indole-3-acetic acid (iaa) has been unequivocally identified in culture supernatants of rhizobium strains by gas chromatography-mass spectrometry. a method for accurately quantitating iaa in bacterial culture supernatants, employing deuterium-labeled iaa as an internal standard, has been developed. similar iaa concentrations were found in culture supernatants of chosen rhizobium mutants (defective in nodule formation) and their corresponding parent strains. since some of the mutants are known to ... | 1982 | 16346073 |
| dilution of liquid rhizobium cultures to increase production capacity of inoculant plants. | experiments were undertaken to test whether peat-based legume seed inoculants, which are prepared with liquid cultures that have been deliberately diluted, can attain and sustain acceptable numbers of viable rhizobia. liquid cultures of rhizobium japonicum and rhizobium phaseoli were diluted to give 10, 10, or 10 cells per ml, using either deionized water, quarter-strength yeast-mannitol broth, yeast-sucrose broth, or yeast-water. the variously diluted cultures were incorporated into gamma-irrad ... | 1982 | 16346075 |
| alteration of the trifoliin a-binding capsule of rhizobium trifolii 0403 by enzymes released from clover roots. | the effect of white clover root exudate on capsules of rhizobium trifolii 0403 was examined. the clover lectin trifoliin a was detected in root exudate of two clover varieties by indirect immunofluorescence with antibody against this lectin purified from clover seed. trifoliin a bound uniformly to encapsulated, heat-fixed cells during 1 h of incubation with root exudate. after 4 to 8 h of incubation, trifoliin a was only bound to one pole of the cells. transmission electron microscopy showed tha ... | 1982 | 16346081 |
| nodulation efficiency of legume inoculation as determined by intrinsic antibiotic resistance. | patterns of intrinsic resistance and susceptibility to different levels of antibiotics were determined for strains of both fast- and slow-growing rhizobia. these patterns were stable to plant passage when they were used to identify rhizobium strains in nodule suspensions or nodule isolates. the method of identification by intrinsic resistance and susceptibility patterns was reliable for identifying strains in field nodules when strains were first isolated from the nodules to provide a standard i ... | 1982 | 16345969 |
| variations in ability of rhizobium japonicum strains to nodulate soybeans and maintain fixation in the presence of nitrate. | this study investigated differences in sensitivity to nitrate of soybean (glycine max cv. davis) symbioses with 16 different rhizobium japonicum strains. when nitrate (20 mm) was added to established symbioses, there were no significant differences in the degree of inhibition of acetylene reduction for any of the 16 strains. when nitrate was present during the establishment of nodules, high levels of nitrate (10 mm) were equally inhibitory on all symbioses, whereas specific strain effects appear ... | 1982 | 16346093 |
| effect of salinity on rhizobium growth and survival. | this study examines the effect of salinity on the growth and survival of rhizobium spp. in culture media and soil. eleven isolates from saline and nonsaline environments were compared. the growth (mean doubling time) of all strains and species tested decreased when the electrical conductivity of the culture medium (yeast extract-mannitol) was raised from 1.2 ms cm to 6.7 ms cm (15% seawater equivalent) or to 13.1 ms cm (28% seawater equivalent). three of eleven strains failed to grow at 13.1 ms ... | 1982 | 16346113 |
| comparison of the pour, spread, and drop plate methods for enumeration of rhizobium spp. in inoculants made from presterilized peat. | inoculants prepared with presterilized peat were enumerated by the pour, spread, and drop plate techniques. results indicated that the three plating methods were interchangeable. the drop plate method was preferred because of its economy in materials and labor. | 1982 | 16346141 |
| a comparative study of the physiology of symbioses formed by rhizobium japonicum with glycine max, vigna unguiculata, and macroptilium atropurpurem. | although rhizobium japonicum nodulates vigna unguiculata and macroptilium atropurpurem, little is known about the physiology of these symbioses. in this study, strains of r. japonicum of varying effectiveness on soybean were examined. the nonhomologous hosts were nodulated by all the strains tested, but effectiveness was not related to that of the homologous host. on siratro, compared to soybean, many strains reversed their relative effectiveness ranking. both siratro and cowpea produced more dr ... | 1982 | 16662732 |
| spectral evidence for a component involved in hydrogen metabolism of soybean nodule bacteroids. | a component with a difference spectrum similar to that of b-type cytochromes which becomes reduced upon the addition of h(2) has been demonstrated in soybean nodule bacteroids. this electron carrier, referred to as component 559-h(2), is present in hydrogenase-positive strains of rhizobium japonicum but has not been detected in mutants that lack hydrogenase activity or in hydrogenase-negative wild-type strains. a positive correlation between concentrations of component 559-h(2) and hydrogenase a ... | 1982 | 16662741 |
| significance of hydrogen evolution in the carbon and nitrogen economy of nodulated cowpea. | the carbon and nitrogen economies of a single cultivar of cowpea (vigna unguiculata (l.) walp.cv caloona) nodulated with either a high h(2)-evolving strain (176a27) or a low h(2)-evolving strain (cb756) of rhizobium were compared. the two symbioses did not differ in total dry matter production, seed yield, nitrogen fixed, the spectrum of nitrogenous solutes produced by nodules for export, or the partitioning of net photosynthate within the plant throughout the growth cycle. detailed examination ... | 1983 | 16662769 |
| cytochromes of rhizobium japonicum 61a76 bacteroids from soybean nodules. | bacteroids of rhizobium japonicum 61a76 were isolated from nodules of field-grown soybean plants by sucrose density gradient fractionation. the major cytochromes, aa(3), b, c, and possibly o were present in the bacteroids throughout the active nitrogen-fixing life of the nodule. this is in contrast with previous reports using other r. japonicum strains in which cyotchromes aa(3) and o were not found. | 1983 | 16662786 |
| a comparison of the surface polysaccharides from rhizobium leguminosarum 128c53 smrif with the surface polysaccharides from its exo mutant. | the surface polysaccharides of rhizobium leguminosarum 128c53 sm(r)rif(r) (parent) and its exo(-1) mutant were isolated and characterized. the parent carries out normal symbiosis with its host, pea, while the exo(-1) mutant does not nodulate the pea. the following observations were made. (a) the parent produces lipopolysaccharide (lps), typical acidic extracellular polysaccharide (eps), and three additional polysaccharides, ps1, ps2, and ps3. the ps1 and ps2 fractions are likely to be the capsul ... | 1983 | 16662808 |
| nitrate and nitrite reduction in relation to nitrogenase activity in soybean nodules and rhizobium japonicum bacteroids. | soybean (glycine max l. cv williams) seeds were sown in pots containing a 1:1 perlite-vermiculite mixture and grown under greenhouse conditions. nodules were initiated with a nitrate reductase expressing strain of rhizobium japonicum, usda 110, or with nitrate reductase nonexpressing mutants (nr(-) 108, nr(-) 303) derived from usda 110. nodules initiated with either type of strain were normal in appearance and demonstrated nitrogenase activity (acetylene reduction). the in vivo nitrate reductase ... | 1983 | 16662897 |
| effect of the host legume on acetylene reduction and hydrogen evolution by rhizobium nitrogenase. | the relative efficiency (re) of n(2) fixation (re = 1 - [h(2) evolved in air]/[acetylene reduced]) was investigated in a rhizobium strain lacking uptake hydrogenase activity (hup(-)). variation in re of such strains presumably reflects changes in the electron allocation coefficient of nitrogenase. by artificially extending the normal dark period of 24-day-old pisum sativum l. cv ;alaska' inoculated with the hup(-)r. leguminosarum strain 3740, reproducible changes in re were obtained. the re show ... | 1983 | 16662950 |
| enzymes of ureide synthesis in pea and soybean. | soybean (glycine max) and pea (pisum sativum) differ in the transport of fixed nitrogen from nodules to shoots. the dominant nitrogen transport compounds for soybean are ureides, while amides dominate in pea. a possible enzymic basis for this difference was examined.the level of enzymes involved in the formation of the ureides allantoin and allantoic acid from inosine 5'-monophosphate (imp) was compared in different tissues of pea and soybean. two enzymes, 5'-nucleotidase and uricase, from soybe ... | 1983 | 16662981 |
| metabolism of c-labeled photosynthate and distribution of enzymes of glucose metabolism in soybean nodules. | the metabolism of translocated photosynthate by soybean (glycine max l. merr.) nodules was investigated by (14)co(2)-labeling studies and analysis of nodule enzymes. plants were exposed to (14)co(2) for 30 minutes, followed by (12)co(2) for up to 5 hours. the largest amount of radioactivity in nodules was recovered in neutral sugars at all sampling times. the organic acid fraction of the cytosol was labeled rapidly. although cyclitols and malonate were found in high concentrations in the nodules ... | 1983 | 16663058 |
| effect of rhizobial strain and host plant on nitrogen isotopic fractionation in legumes. | lotus pedunculatus l., medicago sativa l., macroptilium atropurpureum, glycine max, and trifolium repens l. were grown in a n-free medium and inoculated with one of ten rhizobium strains. dry matter, n content, and delta(15)n values were determined for various plant parts.nodules, with the exception of those from lucerne, were enriched in (15)n relative to atmospheric n. considerable variation was found in delta(15)n values of plant herbage (-4.5 to +0.8). the extent of isotopic discrimination w ... | 1983 | 16663110 |
| host plant cultivar effects on hydrogen evolution by rhizobium leguminosarum. | the effect of host plant cultivar on h(2) evolution by root nodules was examined in symbioses between pisum sativum l. and selected strains of rhizobium leguminosarum. hydrogen evolution from root nodules containing rhizobium represents the sum of h(2) produced by the nitrogenase enzyme complex and h(2) oxidized by any uptake hydrogenase present in those bacterial cells. relative efficiency (re) calculated as re = 1 - (h(2) evolved in air/c(2) h(2) reduced) did not vary significantly among ;felt ... | 1983 | 16663112 |
| role of inosine monophosphate oxidoreductase in the formation of ureides in nitrogen-fixing nodules of cowpea (vigna unguiculata l. walp.). | cell-free extracts from nodules of cowpea (vigna unguiculata l. (walp.) cv caloona:rhizobium strain cb756) prepared in the presence of 15% (v/v) glycerol showed high rates (30 to 60 nanomoles nad reduced per minute per gram fresh weight nodule) of inosine monophosphate oxidoreductase (ec 1.2.1.14) activity. the enzyme was labile (half-life of activity less than 3 hours) but could be stabilized for up to 18 hours by inclusion of the substrates nad and inosine monophosphate in the breaking media. ... | 1983 | 16663115 |
| a rapid regulatory response governing nodulation in soybean. | the number of nodules which develop on the primary root of soybean seedlings (glycine max l. merr) after inoculation with rhizobium japonicum is substantially diminished in the region of the root developmentally 10 to 15 hours younger than the region maximally susceptible to nodulation at the time of inoculation. this rapid inhibition of nodulation has been investigated by inoculating soybean seedlings with rhizobia at two different times, 15 hours apart. living r. japonicum cells, but not heter ... | 1983 | 16663209 |
| phytohormones, rhizobium mutants, and nodulation in legumes : iii. auxin metabolism in effective and ineffective pea root nodules. | high specific activity [(3)h]indole-3-acetic acid (iaa) was applied to the apical bud of intact pea (pisum sativum l. cv greenfeast) plants. radioactivity was detected in all tissues after 24 hours. more radioactivity accumulated in the nodules than in the parent root on a fresh weight basis and more in effective (nitrogen-fixing) nodules than in ineffective nodules (which do not fix nitrogen).for most samples, thin layer chromatography revealed major peaks of radioactivity at the r(f) values of ... | 1983 | 16663219 |
| effect of temperature on nitrogenase functioning in cowpea nodules. | nitrogenase (ec 1.7.99.2) activity of a cowpea (vigna unguiculata (l.) walp cv caloona) symbiosis formed with a rhizobium strain (176a27) lacking uptake hydrogenase and maintained under conditions of a 12-hour day at an air temperature of 30 degrees c (800-1000 microeinsteins per square meter per second) and a 12-hour night at an air temperature of 20 degrees c showed a marked diurnal variation in ratio of nitrogen fixed to hydrogen evolved. as little as 0.3 micromole nitrogen was fixed per micr ... | 1983 | 16663226 |
| identification of rhizobium phaseoli strains that are tolerant or sensitive to soil acidity. | a study was conducted to determine whether the survival of rhizobium phaseoli in acid soils could be predicted on the basis of the tolerance of the organism to acidity in culture. of 16 strains tested, all grew in culture at ph 4.6, but only those that grew at ph 3.8 survived in soils having ph values of 4.1 to 4.6. strains that tolerated the lowest ph values in culture were tolerant of the highest aluminum concentrations. in one acid soil, an acid-tolerant strain was unable to survive in number ... | 1983 | 16346239 |
| congo red absorption by rhizobium leguminosarum. | congo red absorption is generally considered a contraindication of rhizobium. however, r. leguminosarum takes up the dye on yeast extract-mannitol agar. the uptake of congo red varies among strains of r. leguminosarum, as shown elsewhere with strains of r. trifolii and r. meliloti. congo red absorption does not distinguish rhizobia from other bacteria, but may be useful as a strain marker. | 1983 | 16346177 |
| production of antimicrobial and bacteriocin-like substances by rhizobium trifolii. | rhizobium trifolii strains iari and rel-1 produced substances with broad and narrow activity spectra, respectively. reproducible inhibitory zones of various sizes produced by r. trifolii iari (2 to 14 mm) and r. trifolii rel-1 (2 to 6 mm) were detected, depending upon the indicator organism used. the maximum production of these substances by both strains of r. trifolii was observed on l-arabinose agar. a preliminary characterization of the antimicrobial substance produced by strain iari showed r ... | 1983 | 16346202 |
| population changes and persistence of rhizobium phaseoli in soil and rhizospheres. | the impact of legume cultivation on the establishment and persistence of an inoculant strain of rhizobium phaseoli and its ability to compete with a resident population of r. phaseoli for nodule occupancy was examined utilizing strain-specific fluorescent antibodies. the soil (hubbard loamy sand) was inoculated homogeneously with 5 x 10 cells per g of soil and confined in plastic cylinders kept in field plots. inoculated and uninoculated cylinders were either left fallow or planted to two seeds ... | 1983 | 16346203 |
| survival of rhizobium phaseoli in coal-based legume inoculants applied to seeds. | eight coals used as carriers in legume inoculants promoted the survival of rhizobium phaseoli on pinto bean seeds. although peat was more protective, most coal-based inoculants provided >10 viable rhizobia per seed after 4 weeks. | 1983 | 16346218 |
| free-living rhizobium strain able to grow on n(2) as the sole nitrogen source. | a rhizobium strain isolated from stem nodules of the legume sesbania rostrata was shown to grow on atmospheric nitrogen (n(2)) as the sole nitrogen source. non-n(2)-fixing mutants isolated directly on agar plates formed nodules that did not fix n(2) when inoculated into the host plant. | 1983 | 16346220 |
| rapid colony screening method for identifying hydrogenase activity in rhizobium japonicum. | a method has been developed for the rapid screening of rhizobium japonicum colonies for hydrogenase activity based on their ability to reduce methylene blue in the presence of respiratory inhibitors and hydrogen. hydrogen uptake-positive (hup) colonies derepressed for hydrogenase activity were visualized by their localized decolorization of filter paper disks impregnated with the dye. appropriate responses were seen with a number of hup and hup wild-type strains of r. japonicum as well as hup mu ... | 1983 | 16346252 |
| competition among rhizobium leguminosarum strains for nodulation of lentils (lens esculenta). | thirty-one cultures of rhizobium leguminosarum were screened for effectiveness (c(2)h(2) reduction) on lentils (lens esculenta). fluorescent antibodies prepared against three of the most effective strains (hawaii 5-0, nitragin 92a3, and nitragin 128a12) exhibited a high degree of strain specificity; the antibodies reacted strongly with their homologous rhizobia in culture and with bacteroids in nodules. they did not cross-react with one another, and only weakly with 5 of the 47 other r. legumino ... | 1983 | 16346257 |
| physiology of ex planta nitrogenase activity in rhizobium japonicum. | thirty-nine wild-type strains of rhizobium japonicum have been studied for their ability to synthesize nitrogenase ex planta in defined liquid media under microaerobic conditions. twenty-one produced more than trace amounts of acetylene reduction activity, but only a few of these yielded high activity. the oxygen response curves were similar for most of the nitrogenase-positive strains. the strains derepressible for activity had several phenotypic characteristics different from non-derepressible ... | 1983 | 16346295 |
| effects of carrier and temperature on survival of rhizobium spp. in legume inocula: development of an improved type of inoculant. | the effects of inoculant carrier, temperature, and storage period on the survival of rhizobium strains were determined by plate count and most-probable-number analyses. preliminary experiments showed that survival of rhizobia was affected by each of these factors and their interactions. results of further studies indicated that six strains of rhizobia survived better at high temperatures when lyophilized and suspended in an oil carrier as compared to finely ground peat. the oil base inocula cont ... | 1983 | 16346313 |
| evaluation of nitrate reductase activity in rhizobium japonicum. | nitrate reductase activity was evaluated by four approaches, using four strains of rhizobium japonicum and 11 chlorate-resistant mutants of the four strains. it was concluded that in vitro assays with bacteria or bacteroids provide the most simple and reliable assessment of the presence or absence of nitrate reductase. nitrite reductase activity with methyl viologen and dithionite was found, but the enzyme activity does not confound the assay of nitrate reductase. | 1983 | 16346376 |
| competition of rhizobium japonicum strains in early stages of soybean nodulation. | the effects of preexposure of soybean (glycine max l. merrill) roots to rhizobium japonicum strains and subsequent establishment of other strains in the nodules were investigated by using combinations of effective strains (usda 110 and usda 138) and effective-ineffective strains (usda 110 and sm-5). strain usda 110 was a better competitor than either usda 138 or sm-5 on cultivars lee and peking. however, when either of the two less-competitive strains was inoculated into 2-day-old seedlings befo ... | 1983 | 16346400 |
| interaction of agromyces ramosus with other bacteria in soil. | agromyces ramosus occurs in very high numbers in most soils and, based on studies of laboratory isolates, does not require host cells for growth. nevertheless, it attacked and destroyed most of the gram-positive and gram-negative bacterial species tested as possible host organisms. a. ramosus also attacked and destroyed saccharomyces cerevisiae. the possibility of attack on fungi was unclear. among the bacteria serving as hosts were the important soil species azotobacter vinelandii, rhizobium le ... | 1983 | 16346402 |
| possible involvement of a megaplasmid in nodulation of soybeans by fast-growing rhizobia from china. | several isolates from a newly described group of fast-growing acid-producing soybean rhizobia, rhizobium japonicum, were analyzed for plasmid content. all contained from one to four plasmids with molecular weights of 100 x 10 or larger. although most of the isolates shared plasmids of similar size, the restriction endonuclease (bamhi, ecori, and hindiii) patterns of the plasmids from three of the isolates were vastly different. growth in the presence of acridine orange was effective in producing ... | 1983 | 16346403 |
| effect of acidity on the composition of an indigenous soil population of rhizobium trifolii found in nodules of trifolium subterraneum l. | acidity affected which members of an indigenous soil population of rhizobium trifolii nodulated trifolium subterraneum l. cv. mt. barker. in three experiments involving plants grown either in mineral salts agar adjusted to ph 4.8 or 6.8 and inoculated with a soil suspension or grown directly in samples of unamended soil (ph 4.8) or soil amended with caco(3) (ph 6.4), 121 of 151 isolates of r. trifolii were placed into four serogroups. seventy-nine of these isolates were placed into two serogroup ... | 1983 | 16346425 |
| free-living rhizobium strain able to grow on n(2) as the sole nitrogen source. | [this corrects the article on p. 711 in vol. 45.]. | 1983 | 16346430 |
| motility and chemotaxis of rhizobium meliloti in soil. | the spreading of rhizobium meliloti strains in various autoclaved soils was measured by using simple modifications of established techniques. behavioral mutants were used to demonstrate that efficient spreading requires active motility and chemotaxis. the rate of spreading was affected by physical or chemical differences among soils and by changes in water content. | 1983 | 16346435 |
| analysis of poly-beta-hydroxybutyrate in rhizobium japonicum bacteroids by ion-exclusion high-pressure liquid chromatography and uv detection. | ion-exclusion high-pressure liquid chromatography (hplc) was used to measure poly-beta-hydroxybutyrate (phb) in rhizobium japonicum bacteroids. the products in the acid digest of phb-containing material were fractionated by hplc on aminex hpx-87h ion-exclusion resin for organic acid analysis. crotonic acid formed from phb during acid digestion was detected by its intense absorbance at 210 nm. the aminex-hplc method provides a rapid and simple chromatographic technique for routine analysis of org ... | 1983 | 16346443 |
| construction of a rhizobium japonicum gene bank and use in isolation of a hydrogen uptake gene. | a gene bank of rhizobium japonicum dna was constructed by using the broad host range conjugative cosmid plafr1. eighty-three percent of the clones in the bank contained cosmids with insert dna averaging 22.6 kilobase pairs in length. a series of cosmids containing a hydrogen uptake (hup) gene was identified by transferring the gene bank into a h(2) uptake-negative (hup(-)) r. japonicum point mutant (pj17nal) and screening tetracycline-resistant colonies for the ability to grow chemolithotrophica ... | 1983 | 16593268 |
| organization and expression of rhizobium meliloti nitrogen fixation genes. | the boundaries of a nif gene cluster in rhizobium meliloti were determined by tn5 mutagenesis. these genes are clustered within a 14- to 15-kilobase (kb) region that includes the nitrogenase structural genes. sequences within 10 kb on either side of this region are devoid of symbiotically essential gene function. rna blot analysis identified a 5- to 6-kb transcript that corresponds to the nitrogenase structural gene operon. the 5' end of this transcript and its polarity were determined by nuclea ... | 1983 | 16593313 |
| nickel: a micronutrient element for hydrogen-dependent growth of rhizobium japonicum and for expression of urease activity in soybean leaves. | soybean plants and rhizobium japonicum 122 des, a hydrogen uptake-positive strain, were cultured in media purified to remove ni. supplemental ni had no significant effect on the dry matter or total n content of plants. however, the addition of ni to both nitrate-grown and symbiotically grown plants resulted in a 7- to 10-fold increase in urease activity (urea amidohydrolase, ec 3.5.1.5) in leaves and significantly increased the hydrogenase activity (ec 1.18.3.1) in isolated nodule bacteroids. wh ... | 1983 | 16578770 |
| nodule-specific host proteins in effective and ineffective root nodules of pisum sativum. | nodule-specific root proteins - so called nodulins - were identified in root nodules of pea plants by an immunological assay. nodulin patterns were examined at different stages of nodule development. about 30 nodulins were detectable during development. some were preferentially synthesized before nitrogen fixation started, whereas the majority were synthesized concomitantly with leghaemoglobin. some of the nodulins were located within the peribacteroid membrane. ineffective rhizobium strains (a ... | 1983 | 16453462 |
| cloning of the symbiotic region of rhizobium leguminosarum: the nodulation genes are between the nitrogenase genes and a nifa-like gene. | the region of the rhizobium leguminosarum plasmid prl1ji involved in nodulation and nitrogen fixation has been cloned on a series of four overlapping cosmid clones. these clones represent 60 kb of prl1ji dna on which a series of tn5-induced fix and nod alleles have been identified, with the two most distant alleles being separated by 45 kb of dna. the mutant alleles fell into three groups, two clusters of fix alleles separated by one cluster of nod alleles. within one group of fix alleles, dna h ... | 1983 | 16453461 |
| hydrogen recycling by rhizobium leguminosarum isolates and growth and nitrogen contents of pea plants (pisum sativum l.). | the ability to recycle h(2) evolved by nitrogenase is thought to be of importance in increasing the efficiency of n(2) fixation and to be a factor in increasing plant yield in symbiotic systems. to determine whether this ability is a significant factor in the rhizobium leguminosarum-pisum sativum l. system, plants were inoculated with r. leguminosarum isolates which differed in their ability to oxidize h(2) and in their relative efficiency of n(2) fixation. these plants were grown at three level ... | 1983 | 16346248 |
| intergeneric transfer and exchange recombination of restriction fragments cloned in pbr322: a novel strategy for the reversed genetics of the ti plasmids of agrobacterium tumefaciens. | transmission of cole1/pmb1-derived plasmids, such as pbr322, from escherichia coli donor strains was shown to be an efficient way to introduce these plasmids into agrobacterium. this was accomplished by using e. coli carrying the helper plasmids pgj28 and r64drd11 which provide the cole1 mob functions and tra functions, respectively. for example, the broad host-range replication plasmid, pgv1150, a co-integrate plasmid between pbr322 and the w-type mini-sa plasmid, pgv1106, was transmitted from ... | 1983 | 11894957 |
| identification of sequences involved in the polyadenylation of higher plant nuclear transcripts using agrobacterium t-dna genes as models. | sequences in the 3'-untranslated region of two different octopine t-dna genes were analyzed with regard to their significance in polyadenylation. poly(a) addition sites were localized precisely by s1 nuclease mapping with t-dna-derived mrnas isolated from tobacco. the gene encoding transcript 7' contains two aataaa hexanucleotides, respectively 119 bp and 170 bp downstream of the taa stop codon. a single poly(a) site was mapped 24-25 bp downstream of the first aataaa. further, we show that a mut ... | 1983 | 11894958 |
| the conserved part of the t-region in ti-plasmids expresses four proteins in bacteria. | the t-region of ti-plasmids expresses four proteins (mol. wts. 74,000, 49,000, 28,000 and 27,000) in escherichia coli minicells. promoter activities are determined by sequences within the t-region, and the protein-coding regions map in that part of the t-region which is highly conserved in octopine and nopaline plasmids and which is responsible for shoot and root inhibition when expressed in plant cells. three of the regions expressed in bacteria correlate with three regions which are transcribe ... | 1983 | 11894956 |
| physical and genetic characterization of rhizobium meliloti symbiotic mutants. | a set of 19 symbiotic mutants of rhizobium meliloti obtained by a tn5 "suicide plasmid" mutagenesis procedure was characterized genetically and physically. as part of this characterization, we showed that r. meliloti strain 1021, like other r. meliloti strains, contains a very large indigenous plasmid (greater than 300 md) that carries the structural genes for nitrogenase (nifhdk genes). among the 19 symbiotic mutations studied, at least six were shown to reside on the megaplasmid. by a "walking ... | 1983 | 6363587 |
| heat curing of a sym plasmid in a fast-growing rhizobium sp. that is able to nodulate legumes and the nonlegume parasponia sp. | genes involved in nodulation of both legumes and the nonlegume parasponia sp., as well as nitrogenase genes, reside on a large plasmid in a fast-growing rhizobium sp. from lablab purpureus. this plasmid can be cured by incubation at elevated temperatures and can be mobilized by the p1 group plasmid rp1::tn501. | 1983 | 6571729 |
| ultrastructural analysis of ineffective alfalfa nodules formed by nif::tn5 mutants of rhizobium meliloti. | ineffective alfalfa nodules formed by rhizobium meliloti nif::tn5 mutants were examined by light and electron microscopy. r. meliloti nifh::tn5 mutants formed nodules that were similar in structure to wild-type nodules except that nifh- bacteroids accumulated a compact, electron-dense body. in contrast to nodules induced by wild type and nifh mutants, nifdk- r. meliloti mutants induced nodules which contained numerous starch grains and prematurely senescent bacteroids. in addition, meristematic ... | 1983 | 6575011 |
| in vitro expression of nitrogenase activity in parasponia-rhizobium strain anu 289. | rhizobium strain anu 289 derepressed nitrogenase activity under defined in vitro conditions. acetylene reduction was detected both in agar and liquid stationary culture. the strain is capable of nitrogen-fixing nodulation of legumes [such as siratro (macroptilium atropurpureum urb] as well as the non-legumes parasponia andersonii and p. rugosa. nitrogenase activity as high as 40-70 nmol c2h4 per mg protein after 7 days of incubation was detected. strain anu 289 was similar to rhizobium strains 3 ... | 1983 | 6575732 |
| a functional map of the nopaline catabolism genes on the ti plasmid of agrobacterium tumefaciens c58. | the nopaline catabolism (noc) genes are located in a 14.4 kb region on the ptic58 plasmid of a. tumefaciens c58. these genes permit the bacterium to grow on nopaline n2-(1,3-dicarboxylpropyl) arginine, a substrate produced in plant tumors initiated by strain c58. the functions of the noc genes include the use of nopaline and l-ornithine as sole carbon and nitrogen sources. using tn5 insertional mutants, we have identified and mapped the positions of the genes that are responsible for nopaline ca ... | 1983 | 6577260 |
| a general method for the transfer of cloned genes to plant cells. | this paper describes a method for the transfer to plant cells of any cloned gene, regardless of its termini or internal restriction enzyme cleavage sites. a broad host-range intermediate vector, pgv1117, was constructed containing hindiii-23, a right-end t-region fragment of the nopaline plasmid ptic58. using in vivo protection by ecori methylase and ecori linker ligation, a fragment of rabbit chromosomal dna, carrying the beta-globin gene, was inserted into plasmid pgv1117. following transmissi ... | 1983 | 6628995 |
| polysaccharide production by certain antibiotic resistant mutants of rhizobium sp (cowpea miscellany). | 1983 | 6629842 | |
| identification of a rhizobium trifolii plasmid coding for nitrogen fixation and nodulation genes and its interaction with pjb5ji, a rhizobium leguminosarum plasmid. | rhizobium trifolii t37 contains at least three plasmids with sizes of greater than 250 megadaltons. southern blots of agarose gels of these plasmids probed with rhizobium meliloti nif dna indicated that the smallest plasmid, prtt37a, contains the nif genes. transfer of the rhizobium leguminosarum plasmid pjb5ji, which codes for pea nodulation and the nif genes and is genetically marked with tn5, into r. trifolii t37 generated transconjugants containing a variety of plasmid profiles. the plasmid ... | 1983 | 6630147 |
| initial stages in the morphogenesis of nitrogen-fixing stem nodules of sesbania rostrata. | morphogenesis of stem nodules in sesbania rostrata was studied over a period of 6 days after inoculation with an appropriate species of rhizobium. nodulation sites were initially slightly raised, circular areas 0.3 to 0.6 mm in diameter and 4 to 5 mm apart in vertical rows along the length of the stem. each site was underlaid by an adventitious root primordium. a site became susceptible to infection by a specific rhizobium sp. when the root primordium broke through the epidermis, leaving a fissu ... | 1983 | 6630154 |
| high-frequency induction of nodulation and nitrogen fixation mutants of rhizobium japonicum. | more than 50 symbiotic mutants of rhizobium japonicum were isolated by purported plasmid-curing techniques. wild-type r. japonicum strains were grown in liquid culture at 28 or 36 degrees c in different concentrations of acridine orange, ethidium bromide, or sodium dodecyl sulfate for selection of mutants. the symbiotic traits of 133 isolates from nine treatment groups were determined. forty-two isolates were nod- nif+, seven were nod+ nif-, and two were nod- nif-. the nifdh genes were deleted i ... | 1983 | 6630155 |
| rna polymerase from rhizobium japonicum. | dna-dependent rna polymerase (ec 2.7.7.6) from rhizobium japonicum was purified. the subunit structure was found to be beta beta' alpha 2 alpha, with the following apparent molecular weights determined by electrophoresis: mr (beta and beta') 150,000 each, mr (sigma) 96,000, mr (alpha) 40,000, mr (holoenzyme) 490,000, mr (core enzyme) 380,000. the recovery of sigma was 28%. rna polymerase from aerobically grown r. japonicum cells and from nitrogen-fixing cells have the same electrophoretic proper ... | 1983 | 6639271 |
| compatibility of rhizobium japonicum with commercial pesticides in vitro. | 1983 | 6640140 | |
| tryptophan auxotrophs of rhizobium japonicum. | eleven tryptophan-requiring mutants of rhizobium japonicum i-110 ars were isolated after nitrous acid mutagenesis and fell into five groups based on characterization by supplementation with intermediates and enzyme assays. | 1983 | 6643394 |
| presence of a new cytochrome b - like pigment with a peak at 567 nm in various aerobic bacteria. | several physiological groups of bacteria were examined for the presence of a cytochrome b - like pigment which is demonstrable in dithionite-reduced minus substrate-reduced difference spectra. this pigment is characterized by an unusually high alpha band at 567 nm, a low concentration relative to conventional cytochromes, and an inability to be fully reduced by endogenous substrates or nadh. previous studies with one denitrifying and nondenitrifying species of the genus pseudomonas, in paracoccu ... | 1983 | 6652580 |
| purification and electron microscopy of a large plasmid of rhizobium meliloti 41. | a large plasmid dna molecule was purified from rhizobium meliloti 41 by cscl-ethidium bromide density gradient centrifugation. electron microscopic and agarose gel electrophoretic data suggest that addition of alkali effectively removes the chromosomal dna, the plasmid dna can be precipitated from the cleared lysate and no gradient centrifugation is needed for plasmid purification. | 1983 | 6659858 |
| relationship between adenylate cytokinin production and ti plasmid of agrobacterium tumefaciens. | to know whether the tumor-inducing plasmid of agrobacterium tumefaciens carries genetic information of the biosynthesis of cytokinins, the levels of 6-(3-methyl-2-butenyl-amino)purine (ipade) and its 4-hydroxy derivative trans-zeatin (trans-z) and its p-beta-d-ribofuranoside (trans-zr) produced in media by wild-type virulent strain, plasmid-cured avirulent strain and the deletion mutant were compared. the highest levels of ipade and trans-z were found in the culture filtrate of late-log phase gr ... | 1983 | 6664842 |
| physical & chemical studies on lipopolysaccharide of agrobacterium tumefaciens. | 1983 | 6671675 | |
| trifoliin a: a rhizobium-recognition lectin in white clover roots. | 1983 | 6675017 | |
| soybean lectin: does it have an essential role in the rhizobium-soybean symbiosis? | 1983 | 6675019 | |
| [comparative evaluation of the use of glucose and fructose by the oxidative pathway in a strain of rhizobium meliloti]. | the oxidation rate in resting cells of rhizobium meliloti was investigated with either glucose or fructose as substrate. fructose uptake was found to be complete, whereas glucose uptake did not fully occur, yielding 2-kitogluconic acid in the medium. at the end of fructose oxidation, significant levels of this substrate and its derivatives had accumulated in the bacteria. | 1983 | 6681255 |
| effects of culture age on symbiotic infectivity of rhizobium japonicum. | the infectivity of the soybean symbiont rhizobium japonicum changed two- to fivefold with culture age for strains 110 ars, 138 str spc, and 123 spc, whereas culture age had relatively little effect on the infectivity of strains 83 str and 61a76 str. infectivity was measured by determining the number of nodules which developed on soybean primary roots in the zone which contained developing and preemergent root hairs at the time of inoculation. root cells in this region of the host root are suscep ... | 1983 | 6681538 |
| pleomorphism and acetylene-reducing activity of free-living rhizobia. | cowpea-type rhizobium sp. strain 32h1 and rhizobium japonicum usda 26 and 110 grown on a glutamate-mannitol-gluconate agar medium showed increases in the number of pleomorphic cells coincident with their acetylene-reducing activity. pleomorphs appeared to be inhibited in growth nonuniformly, because acetylene-reducing cultures were mixtures of rod, branched (v, y, and t), and other irregularly shaped cells. in contrast, strain usda 10 consistently failed to reduce acetylene, even though it also ... | 1983 | 6822472 |
| methylammonium uptake by rhizobium sp. strain 32h1. | we present evidence that methylammonium is transported into cowpea rhizobium sp. strain 32h1 cells by a membrane carrier whose natural substrate is ammonium. after growth in low (0.2%) oxygen, which is necessary for nitrogen fixation by these cells, respiring rhizobial cells took up [14c]methylammonium to high intracellular levels. cells grown in atmospheric (21%) oxygen did not take up methylammonium. uptake (transport plus metabolism) was maximal in cells harvested in the early stationary phas ... | 1983 | 6826521 |
| a soybean lectin having 4-o-methyl-d-glucuronic acid specificity. | evidence is presented for the presence of a new lectin activity in soybean seeds [glycine max (l.) merrill] that has specificity towards the 4-o-methyl-d-glucurono-l-rhamnan exopolysaccharide produced by certain strains of rhizobium japonicum. bacterial agglutination and precipitin reactions revealed the lectin activity in phosphate-buffered saline extracts of seeds of all cultivars tested, including the "lectinless" varieties. reaction of such extracts with carbohydrate haptens demonstrated tha ... | 1983 | 6838587 |
| genetic analysis of t-dna transcripts in nopaline crown galls. | plant crown gall tumor cells result from the insertion and expression of a defined dna sequence, called t-dna, which is derived from the ti plasmid, harbored by agrobacterium tumefaciens strains. to study the function of the genes of the t-dna of the nopaline ti plasmid, ptic58, a collection of mutants was isolated so that t-dna genes are inactivated either separately or in various combinations. it was found that no single t-dna gene or t-region border is absolutely essential for stable tumor fo ... | 1983 | 6839358 |
| protoporphyrin formation in rhizobium japonicum. | the obligately aerobic soybean root nodule bacterium rhizobium japonicum produces large amounts of heme (iron protoporphyrin) only under low oxygen tensions, such as exist in the symbiotic root nodule. aerobically incubated suspensions of both laboratory-cultured and symbiotic bacteria (bacteroids) metabolize delta-aminolevulinic acid to uroporphyrin, coproporphyrin, and protoporphyrin. under anaerobic conditions, suspensions of laboratory-cultured bacteria form greatly reduced amounts of protop ... | 1983 | 6841317 |
| plant tumors. | 1983 | 6842759 | |
| detection of antibacterial substances in some plant residues and their effect on certain micro-organisms. | the effect of dry residues from several plants, belonging to different families on certain microorganisms in vitro and in vivo, was studied. dry residues of paprica leaves, tomato tops, egg plant leaves, guava leaves, onion peels, garlic tops, wheat straw, sugar cane leaves, cotton leaves, egyptian clover tops, field bean tops or pea tops were examined for the presence of antibacterial substances, using successive extractions with hexane, ethyl ether, ethanol, and water, respectively, for each p ... | 1983 | 6845904 |
| stereochemistry of an alpha, beta-elimination reaction by d-glucosaminate dehydratase. | the proton nmr analysis of d-glucosaminate dehydratase reaction in d2o revealed the incorporation of a deuterium atom at c-3 carbon of the product, 2-keto-3-deoxy-d-gluconate. based on the chemical shift of c-3 proton of the product and the coupling constant characteristic for the c-3 and c-4 axial-axial coupling in the 2c5 pyranose conformation, the deuterium is in the pro-s position. thus, the dehydration of d-glucosaminate by the enzyme proceeds in a retention mode at c-3 carbon. kinetic para ... | 1983 | 6852253 |
| symbiotic properties of c4-dicarboxylic acid transport mutants of rhizobium leguminosarum. | the transport of succinate was studied in bacteroids of an effective, streptomycin-resistant strain (gf160) of rhizobium leguminosarum. high levels of succinate transport occurred, and the kinetics, specificity, and sensitivity to metabolic inhibitors were similar to those previously described for free-living cells. the symbiotic properties of two transposon (tn5)-mediated c4-dicarboxylate transport mutants (strains gf31 and gf252) were determined. strain gf31 formed ineffective nodules, and bac ... | 1983 | 6853448 |
| biosynthesis of amino acids from sucrose and krebs cycle metabolites by rhizobium lupini bacteroids. | the possibility of amino acids biosynthesis from sucrose, metabolites of krebs cycle or glyoxylate and ammonium by intact bacteroids has been studied. the suspension of intact rhizobium lupini bacteroids in phosphate buffer solution ph 7.8 was shown to catalyse the biosynthesis from sucrose and ammonium of some amino acids, such as alanine, aspartic and glutamic acids, glycine and serine. the yield of alanine and aspartic acid was 2.5-3 times higher than that of other amino acids, which were for ... | 1983 | 6855750 |
| a new opine derived from nopaline. | nopaline (n-[4-[(aminoiminomethyl)amino-]-1s-carboxybutyl]-2r-aminopentanedioic acid and isonopaline (n-[4-[(aminoiminomethyl)amino-1s-carboxybutyl]- 2s-aminopentanedioic acid) have been synthesized and separated by crystallization. in addition, a derivative of each of these compounds that forms spontaneously from the parent compounds under the usual crystallization conditions was isolated and characterized. the chemical properties, elemental analysis, 1h-nmr spectrum, and electrophoretic behavi ... | 1983 | 6863246 |
| [demonstration of a metabolic property of rhibozium meliloti usable for its classification]. | fast-growing rhizobium and agrobacterium strans were studied for their behaviour towards two carbohydrates (glucose and fructose) according to the following criteria: acidification and soluble exopolysaccharide production by resting cells. r. meliloti and agrobacterium spp. showed a similar behaviour: in glucose-containing medium, acidification occurred and few exopolysaccharides were produced, whereas in medium supplemented with fructose, a neutral ph was maintained and large amounts of exopoly ... | 1983 | 6870083 |
| involvement of cytochromes and a flavoprotein in hydrogen oxidation in rhizobium japonicum bacteroids. | electron transport components involved in h2 oxidation were studied in membranes from rhizobium japonicum bacteroids. hydrogen oxidation in membranes was inhibited by antimycin a and 2-n-heptyl-4-hydroxyquinoline-n-oxide with ki values of 39.4 and 5.6 microm, respectively. the inhibition of h2 uptake by cyanide was triphasic with ki values of 0.8, 9.9, and 93.6 microm. this result suggested that three cyanide-reactive components were involved in h2 oxidation. h2-reduced minus o2-oxidized absorpt ... | 1983 | 6874637 |
| nif- hup- mutants of rhizobium japonicum. | two h2 uptake-negative (hup-) rhizobium japonicum mutants were obtained that also lacked symbiotic n2 fixation (acetylene reduction) activity. one of the mutants formed green nodules and was deficient in heme. hydrogen oxidation activity in this mutant could be restored by the addition of heme plus atp to crude extracts. bacteroid extracts from the other mutant strain lacked hydrogenase activity and activity for both of the nitrogenase component proteins. hup+ revertants of the mutant strains re ... | 1983 | 6874648 |
| structure of t-dna in roots transformed by agrobacterium rhizogenes. | dna isolated from hairy roots incited on daucus carota by agrobacterium strains harboring the ri plasmid was probed with ri plasmid fragments to identify plasmid sequences transferred and integrated into the plant genome. one hairy root line was incited by an a. rhizogenes natural isolate strain harboring two large plasmids in addition to the ri plasmid. dna from hairy roots incited by this strain contained a total of five nonidentical copies of t-dna which together comprised a t-dna complement ... | 1983 | 6875427 |
| [induced resistance to kanamycin and tetracycline in rhizobium japonicum]. | spontaneous mutants km-r and tc-r of r. japonicum with various levels of resistance to kanamycin (0.8-20 mg/ml) and tetracycline (130-210 micrograms/ml) were isolated. no cross resistance in the mutants was observed. plasmid r68.45 transferred to the wild strains resistance to 210 micrograms/ml of tetracycline and to 20 mg/ml of kanamycin. this plasmid did not practically increase the resistance to tetracycline in mutants tc-r. at the same time it markedly increased the resistance to kanamycin i ... | 1983 | 6881945 |
| morphology of root nodules and nodule-like structures formed by rhizobium and agrobacterium strains containing a rhizobium meliloti megaplasmid. | we examined expression of the megaplasmid prme41b of rhizobium meliloti in two different rhizobium sp. strains and in agrobacterium tumefaciens. transfer of prme41b into these bacteria was facilitated by insertion of a recombinant plasmid coding for mobilization functions of rp4 into the nif region (kondorosi, a., e. kondorosi, c.e. pankhurst, w. j. broughton, and z. banfalvi, 1982, mol. gen. genet., 188:433-439). in all cases, transconjugants formed nodule-like structures on the roots of medica ... | 1983 | 6885919 |
| parasitic origins of nitrogen-mixing rhizobium-legume symbioses. a review of the evidence. | this paper is divided into two sections. the first part (i) reviews the literature on the legume-rhizobium association with emphasis on the processes leading to the establishment of the association. in the second part (ii) it is proposed that the legume-rhizobium association was originally necrotrophic , beginning when the free-living, nitrogen-fixing, saprotrophic rhizobium developed the ability to infect the plant. the pre-infection events, infection processes and nodulation in the colonizatio ... | 1983 | 6370330 |
| special bacterial polysaccharides and polysaccharases. | alcaligenes faecalis var. myxogenes 10c3, which we isolated from soil, produces a water-soluble and an insoluble extracellular polysaccharide. the former (succinoglycan) is composed of glucose, galactose, pyruvic acid and succinic acid (molar proportions 7:1:1:1) with (beta 1-3)-, (beta 1-4)- and (beta 1-6)-glucosidic linkages. the latter (curdlan) is composed entirely of (beta 1-3)-linked d-glucose and forms a resilient firm gel when heated in suspension. the organism also produces extracellula ... | 1983 | 6400487 |
| succinate transport by free-living forms of rhizobium japonicum. | we have demonstrated that the transport of succinate into the cells of rhizobium japonicum strains usda 110 and usda 217 is severely inhibited by cyanide, azide, and 2,4-dinitrophenol, but not by arsenate. these results suggest an active mechanism of transport that is dependent on an energized membrane, but does not directly utilize atp. the apparent km for succinate was 3.8 microm for strain usda 110 and 1.8 microm for strain usda 217; maximal transport velocities were 1.5 and 3.3 nmol of succi ... | 1983 | 6402487 |
| transfer of nitrate reductase genes of the cyanobacterium nostoc muscorum into rhizobium japonicum. | transformation of rhizobium japonicum cb1809 was studied using dna from the cyanobacterium nostoc muscorum atcc 27893. a spontaneous nitrate reductase deficient (nar-) mutant (nr-6) of r. japonicum cb1809 was isolated with a frequency of 8.4 x 10(-7). streptomycin (sm) and neomycin (neo) resistance markers were introduced into strain nr-6, and the resulting strain was designated nr-6 smr neor. experiments with cyanobacterial dna and live cells of strain nr-6 smr neor indicated transformation of ... | 1983 | 6415231 |